CLASS GASTROPODA 
199 
Odostomia notilla Dali and Bartsch, 1909 
Plate 60, fig. 6 
Bulletin 68, United States National Museum, 213; PI. 25, fig. 6. 
Shell very elongate, ovate, yellowish-white. Nuclear whorls deeply 
obliquely immersed in the first of the suceeding turns, above which only 
the tilted edge of the last volution projects. Post-nuclear whorls well- 
rounded, feebly contracted at the sutures, narrowly subtabulately shoul¬ 
dered at the summit. Suture strongly marked. Periphery of the last 
whorl marked by a low raised cord, which renders it decidedly angulated. 
Base short, well-rounded, somewhat pinched in at the umbilical area. 
Entire surface of the spire and base marked by almost vertical lines of 
growth and numerous, very fine, well-incised, spiral striations. Aperture 
ovate, posterior angle acute; outer lip thin; columella slender, slightly 
curved, provided with a fold at its insertion; parietal wall covered with a 
thick callus. Length, 2.7; diameter, 1.3 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206921. Type locality, 
University of California Station 30, off Catalina Island, California. 
Range. Known only from type locality. 
Odostomia nunivakensis Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 194; PI. 22, fig. 6. 
Shell elongate-ovate, deeply umbilicated, milk-white. Nuclear whorls 
small, deeply obliquely immersed in the first of the succeeding turns. Post- 
nuclear whorls increasing very regularly in size, rather high between the 
sutures, well-rounded with strongly tabulated summits. Suture strongly 
marked. Periphery and base of the last whorl well-rounded, umbilicus 
bounded by a slender thread. Aperture elongate-ovate, posterior angle 
obtuse; outer lip thin; columella slender, s-shaped, slightly revolute, free 
from the base, armed with a strong fold near its center. Entire surface 
crossed by fine lines of growth and exceedingly fine, closely spaced, wavy, 
spiral striations. Length, 3; diameter, 1.6 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 159476. Type locality, 
Nunivak Island, Alaska. 
Range. Known only from type locality. 
Odostomia obesa Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 203; Pi. 26, fig. 4. 
Shell large, ovate, yellowish-white. Nuclear whorls very small, very 
deeply immersed in the first of the succeeding turns, above which only the 
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